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Water: Module 4

Basic Course: Key Concepts (Module 4.i)


Module 4. Antidegradation Requirements

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  • The existing uses of a water body must be protected.

  • Within limitations, a State/Tribe has the discretion to allow activities that could degrade water quality to a level that protects existing uses.

  • A State or Tribe's water quality standards must include an antidegradation policy and must specify both when the policy will be applied and what decision-making criteria will be used.

  • A State or Tribe's antidegradation program must include criteria specific to three categories: existing uses, high quality uses, and ONRWs.


  • Antidegradation policy can apply to both point and non-point source activities.

  • The community and other stakeholders must be given an opportunity to provide input as part of the decision-making process regarding a particular application of the policy to a water body.

  • EPA Regional Offices review both new and revised antidegradation programs developed by States and Tribes.

For informational purposes only–Not official statements of EPA policy.

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